The invention relates to an apparatus for dispensing a mixed multi-component compound, in particular for dental purposes.
For producing multi-component dental impression compounds, use is made of units which are designed for accommodating a plurality of component-containing containers and for discharging the components from the containers. On the end side of the units, the containers have exposed outlet openings, to which the inlet openings of a mixing nozzle may be connected. The components come together in the mixing nozzle and leave the latter in the mixed state. Following the mixing operation, the compound hardens. This also applies to those components of the mixture which remain in the mixing nozzle once an impression-compound portion has been produced. Said mixing nozzle is configured such that the components only come together therein at a certain distance from the outlet openings of the cartridges, with the result that the hardening operation within the mixing nozzle remains restricted to a region sufficiently remote from the outlet openings of the containers. This makes it possible for a mixing nozzle which is used for producing an impression-compound portion and is rendered unusable by some of its contents hardening to be left on the unit in order to protect the outlet openings until the next portion is required. It is only then that the mixing nozzle is exchanged for a new one.
In a known unit disclosed in U.S. Pat. No. 5,333,760 the mixing nozzles are retained by a rotatable bayonet closure. A bayonet ring is retained on the mixing nozzle in an axially fixed but rotatable manner and, following the attachment of the nozzle to the outlet openings of the containers, is rotated in order to come into positively locking engagement with a pair of claws on the end side of the containers. The ring involves high outlay in terms of its connection to the mixing nozzle and because a comparatively large number thereof is required, specifically one for each mixing nozzle. This applies correspondingly to another known arrangement (EP-A-730 913), in which the bayonet coupling elements are arranged on the mixing-nozzle housing, which contains, in a rotatable manner relative to the housing, an insert which forms the inlet opening of the mixing nozzle. A design (DE-U-298 20 831) in which a locking means is arranged on the unit for the purpose of retaining the mixing nozzle involves less outlay. This means that it is not necessary for each individual mixing nozzle to be equipped with a bayonet element. However, it has been found that this design does not afford sufficient stability.
The apparatus according to FIG. 4 from U.S. Pat. No. 4,753,536 comprises two component-containing containers which are fixed to one another and bear outlet connection stubs adjacent to one another on the end sides. It is possible to fit onto the outlet connection stubs a mixing nozzle which can be secured in the fitted position by a coupling device. The coupling device comprises a coupling plate which is borne by the outlet connection stubs and forms a guide, running transversely to the direction of the outlet connection stubs, for two coupling slides. The latter can be displaced into a closed position on the guide in opposite directions and bear coupling strips which, in the closed position, engage over a coupling flange of the mixing nozzle through 180.degree. in each case.